Issue #261 - added a couple functions for JCascalog to call into since
it can't deal with ClojureFlow records. Added a test to check
Api.compileFlow() method.

Also added synchronized keyword around all of the public static methods
in Api.

Added Api.flowDef() method so that JCascalog can get a hold of the
FlowDef object if desired.
Fix for issue #215
Added top-level Javadoc comments to the JCascalog Api class to explain ramification of multi-threaded access to this class.
Merge pull request #262 from dkincaid/develop

Issue #261 - added a couple functions for JCascalog to call into since